Method of forming an expansible closure plug



Sept. 1, 1964 I L T. KNOCKE METHOD OF FORMING AN EXPANSIBLE CLQSURE PLUG Filed May 3, 1961 INVENTOR. Z 0w: 7. KNOCKE ATTORNEY United States Patent 3,146,748 METHOD OF FORMHJG AN EXPANSIBL CLOSURE PLUG Louis T. Knocke, 5578 Putnam, Walnut Lake, Mich. Filed May 3, 1961, Ser. No. 107,453 1 Claim. (Cl. 113-121) This invention relates to an improved closure member for an opening in a body which will tightly fit the opening forming a leak proof seal therewith, to the method of forming closure member, and to the method of inserting the closure member into the opening.

The invention is particularly applicable to disc like closure members which are dished and resilient for springable insertion into the opening with the convex side or surface of the dished closure facing inwardly of the opening. Such closures are clearly disclosed in Patent 2,687,228 issued to me August 24, 1954, and this invention is directed to a new and improved disc and the method of forming such a disc.

It is an object of the invention to form a disc closure member of resilient springable material into a concavoconvex contour of greater curvature than the desired curvature of the finished disc; shearing the disc thus formed from a blank to provide a peripheral surface which extends parallel to the axis of the disc; and reforming the disc to a lesser degree of curvature whereby said peripheral surface is rotated to a frusto-conical surface tapering inwardly toward the convex surface.

Another object of the invention is to provide the concave surface of the disc with an outer radially extending portion which lies in a plane at right angles to the axis of the disc, before the reforming operation, and which is rotated with peripheral surface in the reforming operation of the disc to its lesser degree of curvature.

Other objects and advantages of the invention will more fully appear from the following description taken in connection with the accompanying drawings, in which;

FIG. 1 is a cross sectional view of a sheet metal blank showing the step of forming a concavo-convex portion by a dishing or forming operation, the tool being shown in elevation;

FIG. 2 is a cross sectional view of the blank illustrating the shearing action of the disc from the blank;

FIG. 3 is a cross sectional view of the disc illustrating the reforming operation;

FIG. 4 is a cross sectional view of the method of aligning a tool fixture in axial alignment with an opening to be closed by the improved disc;

FIG. 5 is a cross sectional view illustrating the method of assembly of the disc in the tool fixture and in the opening;

FIG. 6 is a cross sectional view illustrating a modified form of disc; and

FIG. 7 is a cross sectional view illustrating another fixture for assembly of the disc shown in FIG. 6.

Referring to the drawings, and particularly to FIG. 1, I have shown a sheet metal blank 10 arranged in suitable dies which produce a dished portion 12 of concavoconvex formation. This operation may be accomplished by a forming tool 14 having a convex nose portion 16 pressing the blank into desired shape in a female die 18. The convex nose portion 16 is provided with an outwardly extending straight portion 20 which lies in a plane at right angles to the axis of the tool 14.

The next step in the operation, shown in FIG. 2, is to shear the concavo-convex portion 12 from the blank 10 on a diameter larger than the concave surface 24 of the dished portion 12 to include the outwardly extending straight portion 20. The tool 14, shown in FIG. 2, may be provided with a convex nose portion 16 and may be the same tool as shown in FIG. 1 having the straight ice portion 20. The shearing operation produces a disc having an outer edge portion 26 which in section lies in a plane parallel to the axis of the disc 12, a concave surface 24 circumscribed by the straight portion 30.

The next operation in the formation of the disc, illustrated in FIG. 3, is to reform the disc in suitable dies to a lesser degree of curvature than produced by the first forming operation illustrated in FIG. 1. In this operation the forming tool 32 is provided with a convex portion 34 having a radius greater than the radius forming the convex surface 16 of the forming tool 14 shown in FIG. 1. Pressure on the tool 32 toward the disc 12 causes the diameter of the disc to slightly increase as the convex and concave surfaces approach a fiat plane, but which are retained with a lesser degree of curvature than produced by the first operation. In this reforming operation the straight portion 30 and the lower edge portion 26 are caused to be rotated and translated from position shown in FIG. 2 to that shown in FIG. 3 producing a frusto-conical surface tapering inwardly toward the axis of the convex surface, and a frusto-conical surface tapering inwardly toward the axis of the concave surface. The included angle between the surfaces 26 and 30 forms a wall engaging edge surface 36.

Referring now to FIGS. 4 and 5, wherein the assembly of such a formed disc is made in an apertured body, I have shown a body portion 40 having an aperture 42. The aperture is counter-bored slightly to provide a frustoconical portion 44 to facilitate partial entry of the disc in the aperture. A tool having a guide fixture 46 and a reciprocable plunger 48 is positioned over the aperture. The guide fixture 46 has a sleeve portion 50 and a counterbored portion 52 which forms a shoulder 54. The plunger 48 has a nose portion 56 provided with a convex surface 58 and an enlarged flange portion 60 which is guided in the counter-bore 52. When the tool is applied over the aperture 42, the plunger is pressed downwardly into the aperture 42, as illustrated in FIG. 4 with the flange 60 abutting the shoulder 54 which limits its downward position. This assures proper alignment of the axis of the plunger 48 with the axis of the aperture 42. The plunger 48 is then raised to a position shown in FIG. 5 and the formed disc 12 is inserted into the guide fixture through an opening 62 in the wall of the sleeve 50 as indicated by the upper dot and dash lines below the raised nose portion 56. The disc 12 rests on the counter-bore 44. The plunger 48 is then forced downwardly forcing the disc into the aperture 42 as indicated by the lower dot and dash lines.

The convex surface 58 of the nose 56 is formed with a radius less than the concave portion 24 to deform the disc. This deformation, caused by the change in curvature of the disc during assembly, results in a reduction of the disc diameter to that of the aperture 42 thereby permitting entry of the disc in the aperture 42. When the nose 56 is returned to its upper position, the resiliency of the metal in seeking to return to its preformed shape results in a further radial pressure to resist dislodging of the disc and forming a tight sealing joint.

FIG. 6 illustrates a modified form of the disc wherein the closure disc 64 is sheared from a flat sheet of spring like material with the sheared edge being in a plane at right angles to the axis of the flat sheet. The outer edge 66 of the disc 64 is bent out of the flat sheet providing an outer sharp edge 68 without machining.

In FIG. 7 the closure disc 64 is applied in the aperture 42 by first placing the downwardly extending edge 66 in the counter-bored portion 44. A suitable tool comprising a plunger 70 and a sleeve 72 slidably mounted on the plunger 70 are used to press the closure disc 64 into the aperture 42. The plunger 70 has a convex nose 74 and a flange 76. The sleeve 72 has an outer diameter which will permit insertion of the sleeve into the aperture 42 and an inner diameter for sliding fit on the plunger 70. A compression spring 78 is arranged between one end of the sleeve '72 and the flange 76. The outer end of the sleeve 72 has a concave bearing surface 86 which fits over the outer edge 68 of the disc 64. Pressure is applied to the plunger 70 compressing the spring "78 and holding the edge of the disc 64 in proper position by the pressure on the sleeve 72. Further pressure on the plunger brings the convex nose 74 into engagement with the central portion of the disc 64. The convex surface 74 has a radius less than the radius of the preformed disc, and further pressure of the plunger causes a deformation of the disc curvature so that the disc can be inserted into the aperture 42. When the plunger is returned to its upper position the resiliency of the material in seeking to return to its preformed shape, results in a radially outwardly pressure forcing the edge 68 into the wall of the aperture in a tight sealing joint.

It is to be understood that the invention is capable of other embodiments and is not limited to the details of construction and arrangement of parts herein illustrated, and that various changes in the size, shape, material and arrangement of parts may be made without departing from the spirit of the invention.

I claim:

The method of forming a closure member from a flat resiliently deformable sheet metal blank which comprises the steps of, forming a dished portion in the metal blank to a greater de ree of curvature than desired in the finished closure member, shearing the dished portion thus formed from the blank on an outer diameter greater than the outer diameter of the dished portion to provide a peripherial surface which is parallel to the axis of the dished portion, the difference in diameters being no greater than the thickness of the sheet metal blank, and reshaping the dished portion to a lesser degree of curvature whereby the peripherial surface is translated from its parallel to the axis position to a position providing a frustro-conical surface, whereby the angle of intersection of the peripherial surface and the surface beyond the periphery of the dished portion form a sharp wall engaging edge.

References Cited in the file of this patent UNITED STATES PATENTS 1,730,377 Northrup Oct. 8, 1929 1,801,006 Jacoby Apr. 14, 1931 2,330,742 Poupitch Sept. 28, 1943 2,687,228 Knocke Aug. 24, 1954 

